Synthesis, Structure, and Catalytic Activity of New μ‐Oxo‐Bridged Diiron(III) Complexes

The preparation and characterisation of two dinuclear iron( III ) complexes with tripodal ligands 1,3‐bis(2′‐pyridylimino)isoindoline (indH) are presented. The μ‐oxo‐bridged diiron( III ) complex [{FeCl(ind)} 2 O] ( 2 ) has been prepared by reacting FeCl 3 ·6H 2 O with indH in methanol solution. Compound [{Fe(ind)(OAc)} 2 O] ( 3 ) was obtained from the reaction of 2 with CH 3 CO 2 Ag in THF. Both compounds were characterised by elemental analysis and UV/vis, IR, and Mössbauer spectroscopy. The X‐ray structure analysis of [Fe 2 O(ind) 2 Cl 2 ]·THF ( 2· THF) revealed a distorted trigonal bipyramidal ( τ = 0.88) coordination geometry around the iron( III ) ion. More importantly, 2 is a good functional model for the activation of small molecules as its 5‐coordinate iron ions can easily coordinate such molecules. This is confirmed by the high catalase‐like activity of 2 , transforming 87% of the excess of H 2 O 2 into O 2 in 1 min. The complexes exhibited monooxygenase‐like activity using H 2 O 2 as the oxidant and oxidise alkanes to alcohols and ketones in acetonitrile in moderate yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)